package xiaohu.day0.HJ10;

import java.util.HashSet;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextLine()) { // 注意 while 处理多个 case
            String str = in.nextLine();
            int length = str.length();
            int index=0;
            int count=0;
            HashSet<Character> hashSet = new HashSet<>();
            while (index < length) {
                char ch = str.charAt(index);
                if (ch >= 0 && ch <= 127) {
                    if (!hashSet.contains(ch)) {
                        count++;
                        hashSet.add(ch);
                    }
                }
                index++;
            }
            System.out.println(count);
        }
    }
}
